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Posts Tagged ‘natural history’

 

Male downy woodpecker (Picoides pubescens)

The male downy woodpecker is a dapper urban resident (iStock, used with permission)

Rushing out the door, I went over the list in my head. Workout pants and layered tees—check. Running shoes—check. Coat, hat, gloves—check. Keys and sunglasses—check. MP3 player—check. Everything was in order as I pulled out of the driveway.

Or so I thought.

Fifteen minutes later I pulled into a parking space at the Power Valley Conservation Nature Center, a 112-acre oasis in suburban St. Louis created by the Missouri Department of Conservation with hilly trails perfect for raising my heart rate for 30-40 minutes. But as I stepped out of the car and began to gather my gear I realized with dismay I’d left behind a critical component—my earbuds.

The thought of a run without my workout mix, and without any caffeine in my system either, was disheartening. I need the motivation of a musical pulse. But I didn’t have time to go back to the house so I set off anyway, prepared to suffer.

About 10 minutes later I realized I was running to a faint drumbeat. At first I thought someone who had NOT forgotten their audio equipment had the volume on their iPod turned up to 11. Once I realized the thumping came from the woods themselves, though, it wasn’t too long before I spotted the drummer, dressed more appropriately for jazz than heavy metal in the stylish black-and-white houndstooth jacket and jaunty red cap of a male downy woodpecker. In spite of the bird’s diminutive size—no more than 6” from head to tail-tip and weighing in at an ounce or less—his wardrobe set him apart on that overcast day from the slate-and-silver hickory bark backdrop.

Downy’s are capable of making a noise disproportionate to their size. When a woodpecker is looking for a mate or claiming a territory, the sound of drumming needs to carry; building a nursery cavity using a beak as a jackhammer isn’t quiet either. But if you’re in the woods and the beat is more bongo than bass, hunger is probably acting as the drummer’s muse. A gentle tap, tap, tap betrays hollow spots beneath the bark where wood-boring insect larvae wait.

drawing of a woodpecker's tongue

Woodpeckers can really stick out their tongues (Florida Center for Instructional Technology, used with permission)

Once dinner has been detected, things get… interesting. That short chisel of a beak hardly prepares you for what’s inside—like many other woodpeckers, the downy has a barbed, sticky, and flexible tongue so long it wraps around the skull when at rest. If ever there was a bird ready-made for rock ‘n roll, it’s the woodpecker. Gene Simmons got nothin’ on these headbangers.

The whole tone of my morning changed in an instant. It’s so easy to carry a personal soundtrack wherever I go that I forget about everything I normally tune out when I turn up the volume. As a result of my oversight, I suddenly had a standing-room-only ticket to a great live performance, one I would surely have missed had this excursion proceeded according to plan.  My run could wait. I stayed for several encores and gave that downy an enthusiastic round of applause as he flew off toward his next gig.

[This post was originally published in January 2011. Hope to have a new installment ready for prime-time soon.]

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© 2011 Next-Door Nature— no reprints without written permission from the author

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Two male turkeys audition but fail to impress the judge (Photo: Teddy Llovet, Creative Commons license)

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I don’t know what American grade school kids are being taught these days—I left Oakville Elementary a couple of decades ago (okay, fine—several decades ago) and since I haven’t had kids of my own I don’t have access to 21st century homework assignments. But I’ll go out on a limb here and bet that most of them know the bald eagle (Haliaeetus leucocephalus) won the 1782 version of American Idol, and that it did so by edging out celebrity judge Benjamin Franklin’s favorite contestant, the wild turkey (Meleagris gallopavo).

That long-ago contest had little in common with the popular modern day version of reality TV. For one thing, neither bird has great pipes. Citizens were never asked to call or text in their votes. Also, the bald eagle has held on to national fame longer than fellow white-headed winner Taylor Hicks, while the turkey hasn’t exactly proven the voters wrong by, say, winning an Academy Award, Jennifer Hudson-style.

On the other hand, we don’t set aside a day each November (or any month, for that matter) on which the eagle takes center stage.  So in honor of Thanksgiving, I’d like to briefly sing the praises of the runner-up… and not just as the star performer at a holiday dinner.

Shortly after Congress immortalized the eagle on the Great Seal of the United States, Franklin shared his disappointment and misgivings over their choice in a letter to his daughter. Given the sparse pelt on his own pate, one might expect ol’ Ben would view the bald eagle as a kindred spirit, or at least harbor a bit of sympathy. Instead, his criticism was as harsh as any doled out by Simon Cowell, describing our new national symbol as “a Bird of bad moral character” who “does not get his Living honestly,” preferring to sup on rotting fish or, worse yet, stealing fresh seafood from more industrious raptors like the osprey (Pandion haliaetus). What’s more, Ben argued the eagle is cowardly, evidenced by how easily it can be driven away by much smaller birds defending their nests and offspring. Not exactly the role model image our fledgling country hoped to cultivate.

The turkey, according to Franklin, is “in Comparison a much more respectable bird,” a “true original Native of America” and a “Bird of Courage” who “would not hesitate to attack” any invader and defend his home turf.

This description might not square with your expectations after years of holiday stories featuring dim-witted, less than inspiring  Butterballs-to-be but the domestic turkey is but a pale and passive imitation of the real-deal.

Wild tom turkeys (as the males are called) will most definitely defend their breeding territory against potential rivals. Large and heavy, they are unexpectedly agile flyers, aggressive fighters, social, sometimes playful, intelligent, and adaptive.  To my knowledge they’ve never been accused of theft or caught dining on carrion (their omnivorous diet consists primarily of acorns and other nuts, seeds, fruit, buds and leaves, insects and the occasional small reptile or amphibian).

As far as moral character goes… well, you know rock stars. Toms strut their stuff in a flamboyant palette of iridescent red, green, purple, copper, bronze, and gold feathers worthy of Adam Lambert. No piercings or tattoos, but oozing cool with a Beat-worthy statement beard of stiff bristles starting just above the wishbone, wattles (flesh hanging from the head and/or neck), caruncles (fleshy growths on the head), snoods (long fleshy object draped across a tom’s beak), spurs and other body art. Their ladies, in keeping with general avian fashion trends, tend to be more conservatively dressed but they can strut like a runway model  when warranted, complete with long legs and outlandish makeup. Out of the spotlight, turkey hens are attentive mothers to their precocial offspring, in contrast to the menfolk, who are polygamous absentee fathers.

(Male bald eagles, it must be said, are actively involved in their children’s upbringing; given his own reputation, Ben might have been well served to heed the old saying about people who live in glass houses before he cast the first stone.)

Like the bald eagle, wild turkeys experienced a perilous decline in their numbers during in the last century, due to overhunting and habitat loss (rather than DDT exposure, as was the case for so many of our birds of prey).  Game agencies took action to protect the species and have been successful in helping the population rebound. So much so, in fact, that turkeys have not only returned to rural fields, pastures, and woodlands but have begun to tour in many major metropolitan areas as well.  In some parts of the country spotting a flock of wild turkeys foraging near a highway, hanging out downtown, or feasting at a backyard bird feeder is no longer a novelty.

That means a growing number of Americans now have a ticket to see  this national treasure up close and personal more than once a year, and at venues other than a serving platter.

For that, I am thankful.

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© 2012 Next-Door Nature—no reprints without written permission from the author (I’d love for you to share my work. Just ask first.). Thanks to these photographers for making their work available through a Creative Commons license: Teddy Llovet (cover); keeva999 (turkey in flight); Mic Stolz (plumage); Peter Patau (men).

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Next-Door Nature, toucan, song sparrow, beak size

When you’re trying to stay cool without air conditioning, it helps to carry a radiator on your face, large or small (Photos: Ame Otoko and Cephas, Creative Commons license).

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A scientists’ work is never done.

That’s because there’s always another layer to peel away, another stone to turn, another angle from which to view the situation.  Case in point—nearly 200 years ago, Charles Darwin made the connection between the size and shape of a finch’s beak and the availability of the seeds they eat; to this very day, no one has been able to produce evidence that undermines his observation and the conclusions he drew from them.

But what if there’s more to a beak than meets the eye?

That’s the question raised by Russell Greenberg of the Smithsonian Conservation Biology Institute. His theory—that beak size may also be an adaptation to temperature regulation and water conservation—has been bolstered by data from two recently published studies.  [Data collected, in part, by a newly minted PhD named Ray Danner. Ray just happens to be a member of my own adopted extended family, and if that name sounds vaguely familiar… well, regular NDN readers may remember that not too long ago I was bragging about another member of this ornithological power couple, Ray’s wife, Dr. Julie Danner.]

black-tailed jackrabbitSome years back, Greenberg noticed a difference in size between the beaks of sparrows living in salt marshes and those of sparrows settled just a kilometer or two further inland. Then a paper published in 2009 reported toco toucans (Ramphastos toco) may lose as much as 60% of their body heat through their long bills, based on thermal imaging and similar to the role played by the large ears of both elephants (Elephantidae) and jackrabbits (Lepus spp.). While many ecologists assumed toucans were a special case, Greenberg wondered—might other birds have evolved larger or smaller beaks to discharge or conserve heat as well?

He chose to test his hypothesis by applying thermal imaging to a subject with a much less prominent proboscis—the song sparrow (Melospiza melodia).  Native to North America, everything about these feathered minstrels is miniature compared to their South American kin. The toucan weighs in at 1-2 pounds (the large bill doesn’t actually tip the scale as much as you might think since it’s mostly hollow) while at 0.4—1.9 ounces the song sparrow is definitely a featherweight.

In the first study, two subspecies were examined. On average, the beak of an Atlantic song sparrow was found to have 17% more surface area than that of the eastern song sparrow, although both birds have similarly sized bodies. Based on the Greenberg team’s calculations, the Atlantic sparrow loses 33% more heat than it’s inland neighbor. The finding suggests beaks may play a role in thermoregulation for a wide variety of bird species.

The ability to stay cool when the ambient temperature rises is critical to survival, but how one gets rid of the excess heat is just as important.  Birds don’t sweat—they pant… and lose not just heat but water in the process. This summer, residents across the U.S. have been reminded just what a precious resource water can be, and never more so than for all the creatures without easy access to a faucet.  Greenberg and his colleagues suggest that a bird’s beak can function like a radiator, releasing heat without losing water. The Atlantic sparrow’s larger bill saves the bird about 8% more water than the smaller beaked eastern sparrow. That may not sound like much but during a hot, dry summer it could be a significant survival advantage.

The second study examined museum specimens of song sparrows collected on the other side of the continent, along the California coast. Sure enough, as maximum temperatures increase, so did beak size… with one caveat.  When the maximum temperature was higher than 98°F (37°C) beaks got smaller… just as was predicted by the original hypothesis. You see, if you took a song sparrow’s temperature the thermometer would read about 105°F (41°C). When the air temperature exceeds the bird’s own temperature, as it does in some regions, a larger beak could actually begin to absorb heat.

While the Smithsonian group has demonstrated a connection between climate and beak size, there’s still plenty of work to be done. For the new hypothesis to garner support, scientists need to see data that ties survival of wild birds to beak size-related heat dissipation.

Meanwhile, the fact that diet influences beak size and shape hasn’t changed—Darwin can continue to rest in peace. But as so often is the case, the more we discover the more we realize just how rich and complex this world and its inhabitants are … even an Earthling as seemingly plain and simple as a sparrow.

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© 2012 Next-Door Nature—no reprints without written permission from the author (I’d love for you to share my work; all you have to do is ask). Thanks to these photographers for making their work available through a Creative Commons license: [from the top] Ame Otoko (toco toucan); Cephas (song sparrow); James Marvin Phelps (black-tailed jackrabbit); Mr. T in DC (house sparrow on drinking fountain); David Craig (song sparrow in hand).

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